No mama likes to see their little one suffering from a fever, so it’s important to know a few basic facts about what to look for when your baby spikes a temp—and when to worry.

Baby’s feeling just fine right now? Happy dance! Pin this one for later.

Here’s what you need to know.

What are the common causes of a fever in a baby?

1. Vaccines

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That boo boo can sting in more ways than one!

Pediatricians recommend monitoring your little one post-vaccination for any signs of a reaction—a mild fever (anything above 100.4 rectally) occurs in some children 12 to 48 hours after the vaccine is given. Slight fevers are to be expected, but for anything over 102*, call your doctor.

2. Teething

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Teething bites.

Studies show that teething may cause an elevation in body temperature, but not one high enough to be considered “fever” territory—generally considered to be anything over 100.4 degrees Fahrenheit. So watch that temp, and put out some frozen chew toys out for baby to gnaw on.

NOMNOMNOM.

3. Infection

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Keep those bugs away from me!

Most true fevers in infants are the result of her work to battle infections she’s encountered in her environment.

As your little one’s immune system builds itself during the first years of baby’s life, she’ll likely experience a lot of bugs that work their way through her system. She got many immunities to infection and disease from you during gestation and any time you spent breastfeeding (thanks, mama!) but she’ll continue to adapt as she gets her vaccines and builds her own independent immune system.

What can I do to help baby?

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Motherly’s expert pediatricians recommend the following strategies when your little one is coping with fever:

Dress in light, loose layers

Bathe your little one in tepid water

Give appropriate doses of fever medication

Call your doctor or nurse’s line to update medical staff as needed (see below)

Monitor baby’s temperature with a highly accurate thermometer—we love this one from Kinsa. (Use promo code MOTHERLY15 for 15% off any Kinsa product.)

When should I worry—or call the doctor?

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If your infant is 8 weeks or younger and has a rectal temperature of 100.4 degrees (38 degrees Celsius) or higher, call your doctor right away — this is considered a medical emergency.

Infants age 7 weeks to 3 months with a fever over 101 warrant an appointment with your doctor within the next several hours.

During this early period of infancy while your baby’s immune system is still developing, she requires much more attention during fever illnesses than she will during later months, so make sure you touch base with a health care provider asap.

“For infants after three months, there is less reason to worry,” Dr. Sears advises.

Here are AAP fever guidelines for infants and toddlers, age 3-24 months—

100.4-101 degrees: Don’t panic —slight fevers are common among infants—vaccinations and even mild viral illnesses can be to blame! Give your baby the correct dosage of a fever reducer (ask your doctor during your next check up!) and use your thermometer to check again in an hour after giving the medication.

102-103 degrees: Dress your baby in something cool and breezy and give your pediatrician a call. You might be able to avoid an unnecessary trip to the doctor’s office with their advice. It will likely include a fever reducer (Motrin or Tylenol) and retaking baby’s temperature in an hour.

104 or higher, but comes down with treatment: Child fevers of 104 degrees or higher that quickly come down to 100 or 101 degrees with the treatment measures are worrisome but not necessarily medical emergencies. If your child is comfortable when the fever comes down and you can keep the temperature down overnight, you can likely wait to call your doctor until the morning.

Fevers of 104 or higher that don’t come down with treatment: High fevers that don’t come down to 101 or 102 (38.3 to 38.9 Celsius) with treatment measures, or fevers that reach as high as 106-106 degrees require immediate medical attention. Your doctor can help you figure out if your child needs to be seen immediately and can also help get your little one comfortable again, so get in touch quickly.

“Some children are happy and playful with fevers of 104 – and this canbe reassuring that they likely do not have a serious infection. On the other hand, a fever of 101 can beworrisome, if your child is lethargic and not responding to you appropriately. Howyour child looks and is acting, is more important than the number on thethermometer,” says Dr. Tiffany Otto Knipe, MD, FAAP and founder of Washington Market Pediatrics.

And remember: You know your child best. If she is showing signs of lethargy, irritability, or other troubling symptoms regardless of temperature, make sure you touch base with your pediatrician.

You’ve got this, mama. Get better, little one!

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